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WatchCheck is an Android app to easily measure the precision of mechanical watches.

The speciality of WatchCheck is, that as reference time only precise time sources such as NTP (network time protocol) and GPS are used, but never the imprecise internal clock of your device (mobile phone or tablet). With GPS you can do precise measurings even when there's no data network available, e.g. when you're abroad.

WatchCheck is implemented in Material Design, so the usage is pretty much self-explaining.

first startfirst start

After starting the app, at first, you have to create a watch in the drawer menu, which can also be accessed by the menu button on the top left of the title bar. Tap on "add watch":

add a new watchadd a new watch

On a new watch, you can not only add the name of the watch, but also a serial number (useful, when you measure multiple watches of the same type) and a comment.

To modify the entry, open the drawer menu and press long on the desired entry. Now you can either modify or delete it.

Important: If you delete a watch, all measurings of that watch are deleted, too!

edit watchedit watch

When a watch entry was created, or a watch is selected from the drawer menu (in this case, you have to press shortly on the entry in the menu), you can add a new measuring and see the previous results (left icon) or a summary (by clicking onto the right icon):


If a comment is available for a log entry (see the info-bubble at the right), you can tap onto that bubble, and you'll see the full comment in a popup window:

comment for a resultcomment for a result

When you press on the "+" button, you come to the measuring screen; when you swipe to the left or right, you can select the measuring period to be shown. By default, the current (rightmost) measuring period is shown.

A new measuring period is usually started, when something significant changed on the watch to be measured, such as a new adjustment, or a first windup after a stop.

The measuring screen looks like that:


On the topmost card, you see the absolutely accurate reference time, either by network (NTP) or GPS or both. If both timesources are active, NTP is preferred.

On the card below, there's the deviation of the last measuring and the current deviation. The current deviation refers to the time of the watch to be measured, which is selected by the time selector below. It's important, that the time of the watch to be measure always refers to the full minute (second hand to zero).

When the watch reaches that time, press the button "Measure (seconds to :00)", and you'll receive a haptic feedback.

On the example screen, when your watch shows 9:53 pm and zero seconds, you have to press the button.

Please remember, that when you have neither a network connection nor GPS receiption, the "Measure" button is inactive and greyed out:

no measure possibleno measure possible

After you've pressed the button, you get to the screen, where you can enter position (at your arm, vertical, horizontal, ...) and the temperature:

Add a log entryAdd a log entry

By selecting "SAVE", the measuring is done and you have a new log. Please take care of the box "New period". As described above, you can start a new measuring period here and take the current measuring as the first one of that period.

After a successful measuring (and also, when you canceled a measuring), you are redirected to the results screen:


If you made an error or if you want to correct a log, you can do this by long pressing the accoring row. You are then redirected to the screen, where you can set position, temperature or probably a new measuring period:

edit logedit log

Only the deviation of the watch cannot be corrected, since it is determined with milliseconds precision. In such a case, you should better delete the log:

delete logdelete log

With the help menu (the three dots top right or the "menu" button on your device), you can show the help page (that very page), and ex- and import the data. The export is made in the new WatchCheck-2 format, the import can handle any WatchCheck format, version 1 and version 2:

import dataimport data

With a simple file manager, you can select the file to be imported. The exported files are put into the root directory of the internal SD card (/storage/sdcard).

To ensure, that you measure (ideally daily) regularily your watch, WatchCheck will display you a daily reminder, every day at the same time:


If you don't want this, or if you want to adjust the time, when the notification is displayed, you can customize this at the settings screen:


In you are on a WLAN connection, then max once a day when you start WatchCheck, the app looks for new articles on and displays them in a popup:

new articles popupnew articles popup

If you don't like that behaviour, you can disable it on the "Settings" menu item:


At any time, regardless of your settings, you can manually look for new and interesting articles (a bit broader) by accessing the menu item "articles on". Any click on one of the articles opens that article in your browser:

Articles on 17jewels.infoArticles on

Required rights

WatchCheck requires a handfull of rights:

- Internet: Access to the NTP timeserver for determination of the reference time and fetching new articles over WLAN

- Network state: Requires to see, whether NTP can be used as time source and to check, if a WLAN connection is active

- Fine location: Required for using GPS as reference time source

- external storage: Ex- and import of the data

- Vibration: Feedback, that a measuring was made

- Boot completed: Ensure, that the daily notifications survive a reboot

Important: No data is transferred onto the internet!


Future plans

Unfortunately, the code base no longer works with current Android libraries, so WatchCheck needs a complete rewrite, for which I really don't have enough time, I'm sorry.



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